The present invention relates generally to rotating end-mill metal cutting tools and more specifically to a particular construction of said machining tools providing significantly improved performance when put into use.
A variety of end-mills for use with rotating milling machines are well known and are being used. Depending on design, such end-mills are generally used in right or left hand cutting operations, spiral and center cutting operations as well as chamfering operations, and the like. Conventionally, these end-mills are constructed with different types of hardened steel as well as tungsten carbide, including tungsten carbide inserts, and are often given additional structural features such as a corner radius at the cutting ends, tapered cutting ends, ball shaped cutting ends, uneven cutting edges for rough milling operations including serrations and still other edge contours. Likewise, these end-mills can be provided for longer wear with wear-resistant coatings including tungsten carbide, amorphous diamond and various nitride compositions. It is still further known with end-mills employing helical cutting flutes to vary the radial rake of the cutting edges with respect to the relative hardness of the particular metal being machined. In such manner a higher radial rake is generally provided for machining softer metals while a lower radial rake is employed for machining harder metals.
In U.S. Pat. No. 4,963,059 there is disclosed a rotary end-mill metal cutting tool with a central axis of rotation therethrough. Said cutting tool includes a cylindrical body with a shank end and a cutting end, said cutting end including an even number of helical cutting flutes being equally spaced in pairs about the circumference of said cutting end. Said equispaced helical cutting flutes are said to be disposed perpendicular to the axis of rotation for the tool body with at least one of said helical cutting flutes being disposed at a helix angle different from the helix angles of the other helical cutting flutes. A ball-nose end-mill having said helical cutting flute construction is also disclosed in said reference.